Mitomycins, anthracyclines, anthraquinones, etc. are known as anti-tumor antibiotics having the quinone moiety [CRC Handbook of Antibiotic Compounds, Volume 3, 1981 (CRC Press U.S.A.)]. Of these, the compounds represented by the following formula are illustrative of antraquinone compounds.
______________________________________ ##STR3## R.sub.A R.sub.B ______________________________________ Pluramycin A COCH.sub.3 X Kidamycin H Z Hedamycin H Y Neopluramycin COCH.sub.3 Z ______________________________________ ##STR4## - ##STR5## - ##STR6## -
Mitomycin C, adriamycin, bleomycin and others are known as anti-tumor antibiotics used for chemotherapy against cancers. However, there has been a constant demand for substances with higher anti-tumor activity because these anti-tumor substances presently available are ineffective against some types of cancer and involve the problem of drug resistance.